Congestive brain oedema associated with a pial arteriovenous malformation with impaired venous drainage

A case of spontaneous brain arteriovenous malformation occlusion: Imaging analysis and clinical debate

The spontaneous occlusion of brain arteriovenous malformations (bAVMs) is a rare event, particularly for unruptured ones. Associated factors include single-venous drainage and small nidus size. Most of the previously reported cases were ruptured bAVMs. We report the case of a middle-aged male patient with an unruptured, rolandic, left-sided bAVM associated with a 30-year history of refractory epilepsy. We documented the spontaneous thrombosis of the venous drainage of the AVM without any sign of bleeding. Finally, we underline the difference between ruptured-induced occlusion and truly spontaneous thrombosis of the bAVMs.

Brain arteriovenous malformations and dural arteriovenous fistulas with extensive venous congestive encephalopathy

In brain arteriovenous malformations (BAVMs) and dural arteriovenous fistulas (DAVFs), when too much blood is drained into the venous system, extensive venous congestive encephalopathy (EVCE) can appear. EVCE in BAVMs and DAVFs can be divided into acute and chronic stages. BAVMs and DAVFs have their own classification systems, but EVCE is not considered in these classification systems and needs to be emphasized. EVCE in BAVMs and DAVFs has unique clinical and imaging features. The clinical presentations usually consist of headache, cognitive impairment, and focal deficits. EVCE in BAVMs and DAVFs has several imaging features, and the venous congestion seen on computed tomography angiography and magnetic resonance angiography can present with the angiographic features of venous reflux and pseudophlebitic pattern. Digital subtraction angiography is the gold standard for the diagnosis. Delayed circulation time is observed. Tortuous, dilated, and engorged veins can be seen. For EVCE from BAVMs and DAVFs, prompt treatment is warranted due to the impairment of extensive brain tissue. Treatments include endovascular treatment (EVT), open surgery, and radiosurgery. EVT is often the primary treatment. Complete elimination in one stage is often difficult. Most of the time, staged treatment has to be chosen. No matter at the acute or chronic stage, aggressive treatment is recommended.

Cerebrovascular Anomalies: Perspectives From Immunology and Cerebrospinal Fluid Flow

Appropriate vascular function is essential for the maintenance of central nervous system homeostasis and is achieved through virtue of the blood-brain barrier; a specialized structure consisting of endothelial, mural, and astrocytic interactions. While appropriate blood-brain barrier function is typically achieved, the central nervous system vasculature is not infallible and cerebrovascular anomalies, a collective terminology for diverse vascular lesions, are present in meningeal and cerebral vasculature supplying and draining the brain. These conditions, including aneurysmal formation and rupture, arteriovenous malformations, dural arteriovenous fistulas, and cerebral cavernous malformations, and their associated neurological sequelae, are typically managed with neurosurgical or pharmacological approaches. However, increasing evidence implicates interacting roles for inflammatory responses and disrupted central nervous system fluid flow with respect to vascular perturbations. Here, we discuss cerebrovascular anomalies from an immunologic angle and fluid flow perspective. We describe immune contributions, both common and distinct, to the formation and progression of diverse cerebrovascular anomalies. Next, we summarize how cerebrovascular anomalies precipitate diverse neurological sequelae, including seizures, hydrocephalus, and cognitive effects and possible contributions through the recently identified lymphatic and glymphatic systems. Finally, we speculate on and provide testable hypotheses for novel nonsurgical therapeutic approaches for alleviating neurological impairments arising from cerebrovascular anomalies, with a particular emphasis on the normalization of fluid flow and alleviation of inflammation through manipulations of the lymphatic and glymphatic central nervous system clearance pathways.

Spontaneous thrombosis in main draining veins of unruptured cerebral arteriovenous malformations: A case report

RATIONALE

Spontaneous obliteration of unruptured arteriovenous malformations (AVMs) is rare. It occurs in <1.5% of cerebral AVMs and only 7 cases have been reported so far. This phenomenon, together with the formation and outcome of cerebral AVMs, remains barely understood. In this work, we presented a case that spontaneous venous thrombosis in main draining veins of an unruptured AVM were confirmed, and reviewed the relevant literature in order to discuss the possible mechanisms.

PATIENT CONCERNS

Clinical data and treatment of a 33-year-old man with a preliminary diagnosis as right parietal mass with secondary epilepsy.

DIAGNOSES

The diagnosis of the mass was a right parietal arteriovenous malformation (AVM) that was 3.5 cm in size and supplied mainly by multiple feeders of right middle cerebral artery (MCA).

INTERVENTIONS

An operation was performed with meticulous hemostasis of the extracranial soft tissue and the AVM was resected completely.

OUTCOMES

The patient's neurological deficits improved postoperatively and he was subsequently discharged 1 week after surgery.

LESSONS

Thrombosis of the draining veins may be due to venous stagnation. Spontaneous venous thrombosis in an unruptured AVM is rare. Spontaneous obliteration of an AVM can occur by 2 mechanisms: occlusion of the feeding arteries or of the draining veins. Surgical or interventional treatment of an unruptured AVM with thrombosed draining veins is highly controversial now. However, we favor an aggressive treatment strategy.

Hybrid surgery for an arteriovenous malformation fed by an accessory middle cerebral artery and drained by a developmental venous anomaly: A case report and literature review

An accessory middle cerebral artery (AMCA), which mainly acts in the collateral circulation of the middle cerebral artery (MCA), is a rare anatomic malformation. Similar to other intracranial vessels, cerebrovascular disease can occur in the AMCA. However, the development of an arteriovenous malformation (AVM) in the AMCA is very rare, especially in conjuction with developmental venous anomalies (DVAs). Here, a rare case of an AMCA combined with an AVM and a DVA was reported. The patient was a 47-year-old female with intracranial hemorrhage at symptom onset. CT and MRI showed lesions in the left Sylvian fissure and insula accompanied by hemorrhage. DSA suggested a left AMCA; an AVM of the AMCA was located in the deep Sylvian fissure. The AVM was diffusely developed and drained into the DVA. The operation was performed in a hybrid operating room. The major feeding artery of the AVM, which was derived from the AMCA, was clipped, then the AVM and DVA were subsequently removed. Intraoperative DSA showed that the AVM and DVA were radically removed. A pathological examination confirmed the presence of an AVM. The patient recovered well and was discharged. Therefore, as highlighted in this case report, rare AVMs can be found in AMCAs and can even occur simultaneously with a DVA. Hybrid surgical treatment can be used to remove AVMs and can lead to an improved prognosis.

Spontaneous thrombosis of the main draining vein revealing an unruptured brain arteriovenous malformation

Haemorrhage is the most frequent revealing condition of brain arteriovenous malformations (bAVMs). We report a rare case of unruptured parietal bAVM revealed by spontaneous thrombosis of the main draining vein, responsible for a focal neurological deficit. The bAVM was embolized in emergency conditions; complete regression of the neurological symptoms was observed within five days after the embolization. Potential mechanisms of such spontaneous thrombosis of the bAVM's main drainage pathway as well as an exhaustive review of the literature concerning this rare revealing condition are presented and discussed.

Pathophysiology of increased cerebrospinal fluid pressure associated to brain arteriovenous malformations: The hydraulic hypothesis

Background:

Brain arteriovenous malformations (AVMs) produce circulatory and functional disturbances in adjacent as well as in remote areas of the brain, but their physiological effect on the cerebrospinal fluid (CSF) pressure is not well known.

Methods:

The hypothesis of an intrinsic disease mechanism leading to increased CSF pressure in all patients with brain AVM is outlined, based on a theory of hemodynamic control of intracranial pressure that asserts that CSF pressure is a fraction of the systemic arterial pressure as predicted by a two-resistor series circuit hydraulic model. The resistors are the arteriolar resistance (that is regulated by vasomotor tonus), and the venous resistance (which is mechanically passive as a Starling resistor). This theory is discussed and compared with the knowledge accumulated by now on intravasal pressures and CSF pressure measured in patients with brain AVM.

Results:

The theory provides a basis for understanding the occurrence of pseudotumor cerebri syndrome in patients with nonhemorrhagic brain AVMs, for the occurrence of local mass effect and brain edema bordering unruptured AVMs, and for the development of hydrocephalus in patients with unruptured AVMs. The theory also contributes to a better appreciation of the pathophysiology of dural arteriovenous fistulas, of vein of Galen aneurismal malformation, and of autoregulation-related disorders in AVM patients.

Conclusions:

The hydraulic hypothesis provides a comprehensive frame to understand brain AVM hemodynamics and its effect on the CSF dynamics.

Extensive white matter changes after stereotactic radiosurgery for brain arteriovenous malformations: a prognostic sign for obliteration?

OBJECTIVE

Perinidal high-signal-intensity changes on T2-weighted magnetic resonance imaging can be seen surrounding radiosurgically treated brain arteriovenous malformations (AVM). Occasionally, these signal intensity changes develop far beyond the irradiated volume. A retrospective analysis of both the pre- and postradiosurgery magnetic resonance imaging and angiographic studies was performed to analyze the cause of these extensive perinidal white matter changes.

METHODS

The pre- and postradiosurgical magnetic resonance imaging and angiographic studies of 30 patients with T2 high-signal-intensity changes surrounding a brain AVM were analyzed retrospectively. Patients were divided into 2 groups on the basis of the extension of the signal intensity changes within or beyond the 10-Gy isodose area. The angiographic analysis was focused on the venous drainage pattern (deep versus superficial), venous stenosis, and the number of draining veins before and after radiosurgery. In addition, the obliteration rate was determined for the 2 subgroups.

RESULTS

Fourteen patients (47%) showed high-signal-intensity changes far beyond the 10-Gy isodose area. A single draining vein was more often present in these patients with extensive T2 hyperintensity signal changes than in the other group. Obliteration was achieved in 12 (88%) of 14 patients with extensive signal intensity changes, as opposed to 8 (50%) of 16 patients in the other group.

CONCLUSION

High-signal-intensity changes after radiosurgery for brain AVMs, far beyond the 10-Gy isodose area on T2-weighted images, are especially seen in brain AVMs draining through a single vein. The higher occlusion rate of brain AVMs under these circumstances is well appreciated.

Ectatic and Occlusive Diseases of the Venous Drainage System of Cerebral Arteriovenous Malformations (AVMs) - with Emphasis on Spectacular Shrinking Neurological Deficits after Embolization

During reviewing cases with AVM, the author noticed that stenotic and occlusive changes of the draining veins are commonly seen in high flow cerebral AVMs. However, little attention has been paid to these venous diseases until ectatic veins, generated in the upstream of the venous system, cause mass effect to the surrounding structures, or redistribution and shunting toward regional veins became insufficient after they are markedly overloaded or occluded. Cases with such venous abnormality are clinically important because of the possibility of dramatic improvement of neurological deficits after embolization of AVMs. Following presenting treatment results of 177 AVM case, the author is going to present five cases with abnormality in the Galenic venous system and two cases with abnormality in cortical veins associating with high flow cerebral AVMs. Consideration will be made on symptomatology and pathophysiologic mechanism of venous abnormalities associating with high flow cerebral AVMs.

Progressive neurological decline after partial spontaneous thrombosis of a Spetzler—Martin Grade 5 arteriovenous malformation in a patient with Leiden factor V mutation: management and outcome

✓ The coexistence of a large intracranial arteriovenous malformation (AVM) and a hypercoagulation disorder is rare. The AVM puts the patient at risk for progressive neurological deficit, seizures, and, most importantly, intracranial hemorrhage. The hypercoagulation disorder may result in an increased risk of stroke. The authors describe a 42-year-old man with a Spetzler—Martin Grade 5 AVM who experienced progressive neurological decline. He was subsequently discovered to have partial thrombosis of the AVM, deep cerebral and cortical venous thrombosis, and a hypercoagulation disorder. Hypercoagulation disorders causing neurological deficits are usually treated with anticoagulant medications; however, this approach was not thought to be safe in the presence of a large AVM. Therefore, the AVM nidus was surgically extirpated and a ventriculoperitoneal shunt was placed to treat the increased intracranial pressure caused by the cortical and deep cerebral venous thrombosis. Subsequently, lifelong oral anticoagulation was prescribed. The patient had a progressive neurological recovery and is now living independently at home. The occurrence of partial or complete spontaneous thrombosis of an AVM nidus should raise the possibility of an underlying hypercoagulation disorder.

Radiologic findings and clinical significance of venous compartment of brain arteriovenous shunts

The venous compartment of brain AVS is closely related to the development of various clinical consequences, including hemorrhage, seizure, and neurologic deficit. Therefore, understanding the venous etiology of the clinical symptoms and the imaging characteristics of partial or complete venous outlet thrombosis is critical for the proper management of patients with brain AVSs.

Role of venous drainage in cerebral arteriovenous malformation surgery, as related to the development of postoperative hyperperfusion injury

OBJECTIVE

To elucidate the role of venous drainage in cerebral arteriovenous malformation (AVM) surgery, with respect to the development of postoperative hyperperfusion injury.

METHODS

For 52 patients with supratentorial AVMs, cortical capillary oxygenation (SaO(2)) was assessed intraoperatively, before and after resection, in the vicinity of the AVMs, by using a microspectrophotometric method. Assessed areas were defined as being related to feeding arteries or draining veins or as distant areas. Patients were divided into three groups on the basis of postoperative angiographic findings, as follows: Group 1, all former draining veins preserved (8 patients); Group 2, > or =1 former draining vein visible (12 patients); Group 3, no former draining veins visible (32 patients). Patients and SaO(2) values were pooled and compared by using paired and unpaired t tests (P < 0.05). Venous circulation times were calculated from digital subtraction angiography films.

RESULTS

The postresectional relative increases in SaO(2) values were highest in draining vein areas (+40.8%, compared with +25% in feeder areas and +25.5% in distant areas). Five postoperative hyperemic complications occurred (9.6%), none in Group 1 (with all draining veins preserved), two (16.7%) in Group 2, and three (9.4%) in Group 3 (with all draining veins occluded). The lowest preresectional SaO(2) values (31.7 +/- 6.2%) were measured in the drainer areas of the five patients who subsequently developed hyperperfusion injuries. Among those patients, postresectional increases in SaO(2) values were significantly greater in drainer areas (+167.8%) than in feeder areas (+28.3%) or distant areas (+25.8%). Postoperative venous circulation times in former draining veins in Group 2 were significantly greater than those in Group 1 (8.9 +/- 1.5 s versus 6.3 +/- 0.6 s). Circulation times in normal veins in the five patients with hyperperfusion injury increased from 5.6 +/- 1.0 seconds (preoperatively) to 8.4 +/- 1.9 seconds (postoperatively).

CONCLUSION

Postoperative hyperperfusion injury after resection of cerebral AVMs can be explained on the basis of unconstrained arterial inflow into cortical areas, which are rendered hypoxic/ischemic by longstanding preoperative venous hypertension. The risk for postoperative breakthrough complications seems higher in the presence of multiple draining veins, which also participate in the physiological venous drainage system of the ipsilateral hemisphere.